hissing sound

[tucknroll]

hey guys, im new here and need some help. I have a 69 charger 383 and I just started hearing a hissing sound right behind the radio area. anyone else have that going on?

[tan top]

 have you got ac ?  does do it all the time when its running ? 

[tucknroll]

yes. I have ac and it starts as soon as I crank it and quits as soon as I kill it. you think it's a hose or something?

[A383Wing]

bad switch, broken nipple on switch, broken hose, bad vacuum pod back there...yer gonna need to find it so your heater doors work properly and also so your engine does not run lean on one cylinder

[tucknroll]

if I cover up the defrost vents I don't hear it but its still there even when the defrost and heat are off.

[A383Wing]

still could be anything I mentioned above....instrument cluster & radio will probably need to be removed and then start car and use stethoscope to pinpoint vacuum leak

[Ghoste]

I agree with Bryan, you should stick a stethoscope under ther and poke around.

[el dub]

Is your carpet wet under the heater box?

[tucknroll]

no its not wet. I was messing around under the dash and must have done something. thanks for the help guys.

[ODZKing]

Vacuum from the brake booster leaking, that can sound like it's coming from under the dash.

[Ghoste]

Very good suggestion, totally forgot about that one and I've had that happen to me.

[tucknroll]

alright guys I found it. the ductwork I guess is what its called to the defrost vents came off. I got in there and put it back on snug and the sound is gone. I guess when it was off, I could hear the radiator fan more. thanks and since im new here, I will try to post more interesting things.

[Ghoste]

What makes you think that wasn't interesting, we are all here because we love this stuff.  Glad to hear theproblem is resolved.